There are quite a few services that I’d never even heard of. Some of them are useful, some of them not so. Some of them you have to be active on like RateItAll and Blogazoo (good luck with that). Some of them have broken sign up links. And some of them are old fashioned link exchanges.
Most of the earliest listed services I’ve been using for the past few years. Out of the new services I’ve discovered via this list, BlogSearchEngine has actually given me the most referrers so far.

I’m not quite sure that listing with all of the services mentioned will help blog or feed popularity in the long run, but hey, it’s an experiment for someone interested in SEO.